Apparatus, systems, and methods for achieving intravascular, thermally-induced renal neuromodulation

Abstract

Apparatus, systems, and methods for achieving thermally-induced renal neuromodulation by intravascular access are disclosed herein. One aspect of the present application, for example, is directed to apparatuses, systems, and methods that incorporate a treatment device comprising an elongated shaft. The elongated shaft is sized and configured to deliver a thermal element to a renal artery via an intravascular path. Thermally-induced renal neuromodulation may be achieved via direct and/or via indirect application of thermal energy to heat or cool neural fibers that contribute to renal function, or of vascular structures that feed or perfuse the neural fibers.

1 - 48 . (canceled) 
     
     
         49 . A method for treating hypertension in a patient in need thereof, the method comprising:
 introducing an intravascular treatment device over a guidewire and into a renal artery of the patient, the intravascular treatment device comprising an elongated shaft extending along an axis, and a distal flexure zone carrying at least one electrode;   manipulating the intravascular treatment device so that the distal flexure zone provides contact between a side of the at least one electrode and an interior wall of the renal artery; and   applying energy to form multiple focal lesions on the interior wall of the renal artery, wherein the lesions are circumferentially spaced along a longitudinal axis of the renal artery,   wherein the at least one electrode has a total surface area (TSA) and an active surface area (ASA), and wherein the intravascular treatment device achieves a ratio of ASA to TSA of between 10% and 50%.   
     
     
         50 . The method of  claim 49 , wherein applying energy at least partially modulates neural fibers that contribute to renal function. 
     
     
         51 . The method of  claim 49 , wherein applying energy denervates a kidney of the patient. 
     
     
         52 . The method of  claim 49 , wherein applying energy comprises delivering a monopolar electric field via the at least one electrode. 
     
     
         53 . The method of  claim 49 , wherein applying energy comprises supplying a continuous delivery of radiofrequency (RF) energy to the electrode. 
     
     
         54 . The method of  claim 49 , wherein applying energy comprises exposing the renal artery to a temperature above about 60° C. and less than about 90° C. 
     
     
         55 . The method of  claim 49 , wherein applying energy comprises exposing the renal artery to a temperature above about 60° C. and less than about 80° C. 
     
     
         56 . The method of  claim 49 , wherein the at least one electrode is generally cylindrical. 
     
     
         57 . The method of  claim 49 , wherein the one or more thermal heating effects comprise thermal ablation of tissue on the interior wall of the renal artery. 
     
     
         58 . The method of  claim 49 , wherein introducing an intravascular treatment device into a renal artery of the patient comprises routing the intravascular treatment device through a 6 French guide catheter. 
     
     
         59 . The method of  claim 49 , wherein the intravascular treatment device further comprises a temperature sensor located proximate to the at least one electrode. 
     
     
         60 . The method of  claim 49 , wherein the at least one electrode comprises multiple electrodes. 
     
     
         61 . The method of  claim 49 , further comprising delivering a thermal fluid into the renal artery. 
     
     
         62 . The method of  claim 61 , wherein the thermal fluid comprises saline. 
     
     
         63 . The method of  claim 49 , wherein each of the lesions covers approximately 20 percent to 50 percent of a circumferential area surrounding the renal artery. 
     
     
         64 . The method of  claim 49 , wherein each of the lesions covers approximately 20 percent to 30 percent of a circumferential area surrounding the renal artery. 
     
     
         65 . The method of  claim 49 , further comprising monitoring feedback and altering treatment delivered to the renal artery in response to the feedback. 
     
     
         66 . The method of  claim 49 , wherein the intravascular treatment device comprises a catheter apparatus.